1. Field of the Invention
Generally, this invention relates to compressive receivers and more particularly to compressive receivers that are not limited in instantaneous bandwidth by the bandwidth characteristics of the delay lines.
2. Description of Prior Art
A compressive receiver is a wideband receiver capable of fine-frequency resolution and processing of numerous electrical signals that are simultaneously provided to the receiver. Traditional channelized receivers differ from compressive receivers in that simultaneously received signals processed by channelized receivers are outputted in parallel whereas simultaneously received signals processed by compressive receivers are converted to time-compressed pulses outputted in series in the order of their signal frequency. By measuring the position of each relatively narrow signal pulse provided by the compressive receiver with respect to time, the frequency of each input signal can be determined. Since the group of relatively narrow signal pulses is compact and each pulse is relatively close timewise to adjacent pulses, high speed logic circuits are required to process the electrical signal pulses produced by compressive receivers.
Compressive receivers have the ability to separate a multitude of input signals having different frequencies even if the input signals overlap. Traditional research and development efforts concerning compressive receivers have concentrated on the use of local oscillators (LO's) and dispersive delay lines (DDL's), specifically surface acoustic wave (SAW) DDL's, to process input signals to obtain outputs consisting of relatively narrow compressed signals which approximate single pulses. However, compressive receivers which utilize SAW DDL's are limited in the instantaneous bandwidth of the input signal by the bandwidth of the DDL's. This limitation is currently between one gigahertz and two gigahertz. In other words, traditional SAW DDL compressive receivers may not be capable of processing input signals having frequencies above two gigahertz.